1. Field of the Invention
This invention relates generally to encoding systems and more particularly to a method and system for pre-processing techniques for deblocking applied in an encoding loop to improve image quality and simplify decoding.
2. Description of the Related Art
Transmission of video data has become more popular as network bandwidth has increased to handle the bandwidth required for video data having an acceptable quality level. Video data requires a high bandwidth, i.e., many bytes of information per second. Therefore, video compression or video coding technology reduces the bandwidth requirements prior to transmission of the video data. However, the compression of the video data may negatively impact the image quality when the compressed video data is decompressed for presentation. For example, block based video compression schemes, such as Motion Picture Expert Group (MPEG) coding standard, suffer from blocking artifacts which become visible at the boundaries between blocks of a frame of the video image.
FIG. 1 is a simplified schematic diagram of a video coding system. Video capture device 100 captures image data. The image data is then compressed according to a compression standard through encoder 102. The compressed image data is then transmitted over network 104 to decoder 106. Decoder 106 may include post-processing block 108, which is configured to compensate for blocky artifacts. The decompressed image data that has been post processed is then presented on display monitor 110.
Thus, post-processing block 108 includes the capability to offset blocky artifacts, e.g., low pass filters applied to the spatial domain attempt to compensate for the artifacts introduced through the compression standard. However, one shortcoming with current post-processing steps is their computational complexity, which requires about 30–50% of the total computational power needed in the decoder, not to mention the dedication of compute cycles for post-processing functions. It should be appreciated that this type of power drain is unacceptably high for mobile terminals, i.e., battery enabled consumer electronics, such as terminals incorporating thin film transistors (TFT) technology, super-twisted nematic (STN), and mobile digital-thin film diode (MD-TFD). Another shortcoming of the low pass filters currently being used is that the amount of time for the filtering operation may cause a noticeable delay in the presentation of the image. This delay is especially noticeable with respect to portable electronic computing systems due to the limited resources of the embedded systems controlling these devices.
As a result, there is a need to solve the problems of the prior art to provide a method and system for simplifying or eliminating the need for post-processing operations for minimizing blocking artifacts.